Hello –
I have to install a backflow preventor where the city waterline enters the house.
The town is having folks install them whenever the chance comes up.
Well, it’s our turn.
Anyway, it’s not a big deal but a friend told me this turns the indoor water system into a closed system and the hotwater heater can cause the pressure to build up and the pressure relief can pop open occasionally.
It makes sense and I’m glad he bought this up.
(The inspector never told me about this…)
If the pressure relief valve on the water heater is known to be in good working order and the drain tube is routed to a floor drain, will this suffice ?
Or would an expansion tank be required or help prevent frequent popping of the relief valve ?
Thanks for any feedback or input,
Alan
Replies
"If the pressure relief valve on the water heater is known to be in good working order and the drain tube is routed to a floor drain, will this suffice ?
Or would an expansion tank be required or help prevent frequent popping of the relief valve ?"
Try reading that little yellow label that comes on the P/T valve: test yearly; pull and have checked by a plumber every 3 years! (Right!!!)
Add the expansion tank, IMHO.
Thanks, Bob, for the very speedy reply.
Thank-you for suggesting going ahead with the expansion tank.
I guess I'm trying to find out if an expansion tank is commonly found in homes with backflow preventors.
I'll go to my favorite local plumbing supply house (not Home Dump or Lowes) and see what's going on.
Take care,
Alan
You definitely need the expansion tank. The check valve in the backflow preventer turns your water system into a closed system and the expansion of water in the hot water tank will pop the expansion valve every day!! They don't alwaays reclose automatically unless you lose water pressure.
A backflow preventer on a residence? What ridiculous-overboard-someone has a little knowledge-waste of money. Does the town pay for the installation? ...that's not a mistake, it's rustic
Jeff -
Well....ridiculous or not, that's the rule in our town.
I'm just trying to comply by installing it but the building up of pressure issue came up.
Just trying to prevent other problems that is caused by what I thought was a simple matter of sweating on the valve.
Yes, it is stupid but they are paranoid about contamination.
Alan
To report back....
Picked up the valve and an Amtrol expansion tank.
It turns out the city about an hour north from us had a contamination that affected 10,000 people several years ago. (A water hose stuck in a bucket of insecticide by a contractor.)
Also, a town closer by had a problem that prompted a mandatory installation in all homes.
Some towns, such as ours, have been gradually getting at existing homes in addition to requiring new construction to have them.
Some folks are having to install expansion tanks after having leak problems, others haven't had any problems.
Alan
I had a similar problem on a house with extreme water pressure in the city line. I solved the problem with a pressure relief valve that went on the outside of the house at a hosebib. Since expanded water couldn't back upm past my pressure regulator it would drip at the relief valve outside. It was manufactured by Watts. This was a lot less costly than an expansion tank or the damage that would have occurred over time to the piping. Why I had to do it to a forty year old house when noone else had had a problem is beyond me.
The worst part of having a backflor preventor is the annual testing and recertification they may require.
joe d
In cold climates this is dangerous and should not be used as a fix. Also there are some very good reasons to install a backflow prevention device. Someone doesn't know what all can and does happen in the real world.
Of course, all plumbing must be protected from freezing. I never said not to install the backflow preventer. The pressure relief valve is in lieu of the expansion tank. The only drawback I am aware of is that the water is wasted.
Sorry, but to install a relief valve like you mentioned in cold climates is still dangerous. It will freeze up.
The backflow preventor will be installed inside the house just past the main shutoff valve (located well inside a heated area of the house)and the expansion tank at the water heater.
Theres is no exposed pipe outside.
We have weather in the teens and sometimes below.
Please tell me if I'll have freezing problems.
nope
Thanks, Wet Head -
Just wanted to make sure I'm not overlooking something.
Alan